Hi,
In the first query u need to include a '+' sign for all the conditions which involves the the second table, that is table_b in this case.

So the query:
[CODE=oracle]select a2 from table_a,table_b where table_a.a1=tabl e_b.b1 (+) and table_b.b1=9999 99[/CODE]
becomes

[CODE=oracle]select a2 from table_a,table_b where table_a.a1=tabl e_b.b1 (+) and table_b.b1(+)=9 99999[/CODE]
so that the the result...